<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div></div>
<script>
    var div = document.querySelector('div');
    var time = 5;
    setInterval(function () {
       if (time == 0) {
           location.href = 'http://www.baidu.com';
       }  else {
           div.innerHTML = '跳转还剩'+time+'秒';
           time--;
       }
    },1000)
</script>
</body>
</html>